Do you need to know your own blood group?

Do you need to know your own blood group?

No .. well, that is the short answer. Actually we mean ‘no, not usually’. We explain why shortly. But first of all ..

What is a blood group?

A blood group is a characteristic (face) of a red blood cell. There are 4 main blood groups (types of blood) – A, B, AB and O. Your blood group is determined by the genes you inherit from your parents. You will have one type of face on all your red blood cells.

Each group can be either RhD positive or RhD negative, which means in total there are 8 blood groups – like 8 different faces, or hat and scarf combinations.

So. Do you need to know your own blood group?

No. Why? Doctors (and you) only need to know your blood group, if you are going to receive a blood transfusion (i.e. blood donated fr0m someone else). As most people never receive a blood transfusion in their lives, you do not need to know it.

A bit more about what blood groups are ..

Antibodies and antigens

Blood is made up of red blood cells, white blood cells and platelets in a liquid called plasma. Your blood group is identified by antibodies and antigens in the blood.

Antibodies are proteins found in the blood. They’re part of your body’s natural defences. They recognise foreign substances, such as germs, and alert your immune system, which destroys them.

Antigens are protein found on the surface of red blood cells.

The ABO system

There are 4 main blood groups defined by the ABO system:

• Blood group A – has A antigens on the red blood cells, with anti-B antibodies in the blood
• Blood group B – has B antigens with anti-A antibodies
• Blood group O – has no antigens, but both anti-A and anti-B antibodies
• Blood group AB – has both A and B antigens, but no antibodies.

Blood group O is the most common blood group. Almost half of the UK population (48%) has blood group O.

What happens if you receive a blood transfusion from the wrong group?

It depends [“Thanks CKDEx!” Ed]. Receiving blood from the wrong ABO group can be life-threatening. For example, if someone with group B blood is given group A blood, their anti-A antibodies will attack the group A cells.

This is why group A blood must never be given to someone who has group B blood and vice versa.

As group O red blood cells do not have any A or B antigens, it can safely be given to any other group. In this way it is called the ‘universal donor’ (of blood).

As group AB red cells have both A and B antigens, but no antibodies, it can safely receive blood from any group. It is called the ‘universal receiver’ (of blood).

How is blood group tested, if that is needed?

To find your blood group – which doctors call ‘ABO typing’ – a blood sample needs to be sent to the laboratory. You can know within an hour.

Summary

We have explained do you need to know your own blood group? No, not usually. We hope you understand it better now.

Last Reviewed on 9 March 2024